将方法转换为linq到实体表达式以查询实体框架

如何解决将方法转换为linq到实体表达式以查询实体框架

|| 我有这个问题，我真的不知道如何解决。在放弃这个问题之前，我问了两个问题，但没有为我的情况找到正确的答案。这是详细的问题。我有一个接口和默认实现：

public interface IEntityPriceDefinition
{
    PriceDefinition PriceDefinition { get; }

    bool IsMatch(long additionId);

    bool IsMatch(long? entityId,long? inviterId,long? routeId,long? luggageTypeId);

    bool IsMatch(long? entityId,long? luggageTypeId,long additionId);

    bool IsMatch(long? entityId,Task3 task);

    bool IsMatch(long? entityId,Task3 task,long additionId);
}

public class EntityPriceDefinition : IEntityPriceDefinition
    {
        private PriceDefinition _PriceDefinition;
        private Func<long?,bool> _IsEntityIdMatch;
        private Func<Task3,long?> _TaskValue;

        public PriceDefinition PriceDefinition { get { return _PriceDefinition; } }

        internal EntityPriceDefinition(
            PriceDefinition priceDefinition,Func<long?,bool> isEntityIdMatch,Func<Task3,long?> taskValue)
        {
            _PriceDefinition = priceDefinition;
            _IsEntityIdMatch = isEntityIdMatch;
            _TaskValue = taskValue;
        }

        public bool IsMatch(long additionId)
        {
            return PriceDefinition.AdditionsPrices.Any(x => x.AdditionId == additionId);
        }

        private bool IsMatch(long? inviterId,long? luggageTypeId)
        {
            bool isMatch = inviterId.HasValue || routeId.HasValue || luggageTypeId.HasValue;
            if (isMatch)
            {
                if (PriceDefinition.InviterId.HasValue && inviterId.HasValue)
                {
                    if (PriceDefinition.InviterId.Value != inviterId.Value) { isMatch = false; }
                }
                if (PriceDefinition.LuggageTypeId.HasValue && luggageTypeId.HasValue)
                {
                    if (PriceDefinition.LuggageTypeId.Value != luggageTypeId.Value) { isMatch = false; }
                }
                if (PriceDefinition.RouteId.HasValue && routeId.HasValue)
                {
                    if (PriceDefinition.RouteId.Value != routeId.Value) { isMatch = false; }
                }
            }
            return isMatch;
        }

        public bool IsMatch(long? entityId,long? luggageTypeId)
        {
            return _IsEntityIdMatch(entityId) && IsMatch(inviterId,routeId,luggageTypeId);
        }

        public bool IsMatch(long? entityId,long additionId)
        {
            return IsMatch(entityId,inviterId,luggageTypeId) && IsMatch(additionId);
        }

        public bool IsMatch(long? entityId,Task3 task)
        {
            bool isMatch = _IsEntityIdMatch(_TaskValue(task)) &&
                IsMatch(task.InviterId,task.RouteId,task.LuggageTypeId);

            for (int i = 0; i < PriceDefinition.Rules.Count && isMatch == true; i++)
            {
                object value = task.GetFieldObjectValue(PriceDefinition.Rules[i].FieldName);
                isMatch = PriceDefinition.Rules[i].IsMatch((value ?? string.Empty).ToString());
            }
            return isMatch;
        }

        public bool IsMatch(long? entityId,task) && IsMatch(additionId);
        }
    }

我也有3个类使用默认实现来实现IEntityPriceDefinition。这是其中两个类（第三个是相同的）：

public class CustomerPriceDefinition : IEntityPriceDefinition,IDataEntity
    {
        private IEntityPriceDefinition _EntityPriceDefinition;

        public virtual long PriceDefinitionId { get; set; }
        public virtual long CustomerId { get; set; }
        public virtual PriceDefinition PriceDefinition { get; set; }

        public CustomerPriceDefinition()
        {
            _EntityPriceDefinition = new EntityPriceDefinition(
                PriceDefinition,entityId => entityId.HasValue && entityId.Value == CustomerId,t => t.CustomerId);
        }

        public bool IsMatch(long additionId)
        {
            return _EntityPriceDefinition.IsMatch(additionId);
        }

        public bool IsMatch(long? customerId,long? luggageTypeId)
        {
            return _EntityPriceDefinition.IsMatch(customerId,luggageTypeId);
        }

        public bool IsMatch(long? customerId,long additionId)
        {
            return _EntityPriceDefinition.IsMatch(customerId,luggageTypeId,additionId);
        }

        public bool IsMatch(long? customerId,Task3 task)
        {
            return _EntityPriceDefinition.IsMatch(customerId,task);
        }

        public bool IsMatch(long? customerId,task,additionId);
        }
    }

public class WorkerPriceDefinition : IEntityPriceDefinition,IDataEntity
    {
        private IEntityPriceDefinition _EntityPriceDefinition;

        public virtual long PriceDefinitionId { get; set; }
        public virtual long WorkerId { get; set; }
        public virtual PriceDefinition PriceDefinition { get; set; }

        public WorkerPriceDefinition()
        {
            _EntityPriceDefinition = new EntityPriceDefinition(
                PriceDefinition,entityId => entityId.HasValue && entityId.Value == WorkerId,t => t.WorkerId);
        }

        public bool IsMatch(long additionId)
        {
            return _EntityPriceDefinition.IsMatch(additionId);
        }

        public bool IsMatch(long? workerId,long? luggageTypeId)
        {
            return _EntityPriceDefinition.IsMatch(workerId,luggageTypeId);
        }

        public bool IsMatch(long? workerId,long additionId)
        {
            return _EntityPriceDefinition.IsMatch(workerId,additionId);
        }

        public bool IsMatch(long? workerId,Task3 task)
        {
            return _EntityPriceDefinition.IsMatch(workerId,task);
        }

        public bool IsMatch(long? workerId,additionId);
        }
    }

我还为这些类提供了存储库接口和默认实现：

public interface IEntityPriceDefinitionRepository<T> : IRepository<T>
    where T : class,IEntityPriceDefinition,IDataEntity
{
    IEnumerable<T> GetMatchPrices(
        Guid companyId,bool? isSuggested,bool? isValid,long? entityId,Func<IQueryable<T>,IOrderedQueryable<T>> orderBy,Expression<Func<T,object>>[] includes);

    IEnumerable<T> GetMatchPrices(
        Guid companyId,long additionId,object>>[] includes);
}

public class EntityPriceDefinitionRepository<T> : BaseRepository<T>,IEntityPriceDefinitionRepository<T> where T : class,IDataEntity
{
    private IEnumerable<T> GetMatchPrices(
        Guid companyId,bool>> isMatch,object>>[] includes)
    {
        var filters = new Expression<Func<T,bool>>[]{
            x => x.PriceDefinition.CompanyId == companyId,x => x.PriceDefinition.IsDeleted == false,x => !isValid.HasValue || x.PriceDefinition.IsValid == isValid.Value,x => !isSuggested.HasValue || x.PriceDefinition.IsSuggested == isSuggested.Value,isMatch
        };

        return GetQuery(filters,orderBy,includes);
    }

    public IEnumerable<T> GetMatchPrices(
        Guid companyId,object>>[] includes)
    {
        return GetMatchPrices(companyId,isSuggested,isValid,//////////////////  THIS CAUSE THE EXCEPTION MENTIONED BELOW:  //////////////////
            x => x.IsMatch(entityId,luggageTypeId),additionId),includes);
    }        
}

而类存储库类就是：

 public class CustomerPriceDefinitionRepository :
        EntityPriceDefinitionRepository<CustomerPriceDefinition> { }

    public class WorkerPriceDefinitionRepository :
        EntityPriceDefinitionRepository<WorkerPriceDefinition> { }

当我调用CustomerPriceDefinitionRepository \的GetMatchPrices方法时，发生了问题。关于上面标记的方法，它总是以异常结束： LINQ to Entities无法识别方法\'Boolean IsMatch（System.Nullable1[System.Int64],System.Nullable1[System.Int64]，System.Nullable1[System.Int64],System.Nullable1[System.Int64]）\'，并且该方法无法转换为商店表达式。 Ladislav Mrnka在这里回答我使用模型定义的函数，但我希望所有代码都在其类中，而不是xml中。此外，此代码与edmx使用的巨大范围无关。另外，我相信，为了使用模型定义的函数，我将必须定义3种方法-每个IEntityPriceDefinition子类一个IsMatch。我真的不知道如何解决这个问题，对于这种情况，尤其是对于这种非简单结构，什么是最佳解决方案？我会寻求任何帮助。

解决方法

我在EntityPriceDefinition中添加了一个静态方法：

   public static Expression<Func<CustomerPriceDefinition,bool>> IsMatchExpression(
        long? entityId,long? inviterId,long? routeId,long? luggageTypeId,long additionId)
    {
        return x =>
            (entityId.HasValue && entityId.Value == x.CustomerId) &&
            (inviterId.HasValue || routeId.HasValue || luggageTypeId.HasValue) &&
            !(
                (x.PriceDefinition.InviterId.HasValue && inviterId.HasValue &&
                    x.PriceDefinition.InviterId.Value != inviterId.Value) ||

                (x.PriceDefinition.LuggageTypeId.HasValue && luggageTypeId.HasValue &&
                    x.PriceDefinition.LuggageTypeId.Value != luggageTypeId.Value) ||

                (x.PriceDefinition.InviterId.HasValue && inviterId.HasValue &&
                    x.PriceDefinition.InviterId.Value != inviterId.Value)
            ) &&
            x.PriceDefinition.AdditionsPrices.Any(a => a.AdditionId == additionId);
    }

这样，表达式便知道如何将其转换为查询。

将方法转换为linq到实体表达式以查询实体框架

如何解决将方法转换为linq到实体表达式以查询实体框架

解决方法

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